Device for a projectile

ABSTRACT

A flare releasing missile has a casing including the propellant charge and a hollow projectile fitted to the casing and housing a flare and a parachute therefor. The projectile including its bottom plate is lengthwise split and the projectile parts thus formed are held together by a cap fitted upon the bottom of the projectile until the same is fired. Upon firing of the projectile the cap is forced off thereby freeing the projectile parts and thus the flare with its parachute. The projectile parts are thrown out of the trajectory of the flare by the centrifugal force acting upon the parts due to the spin imparted to the projectile by the rifling in the gun barrel.

ilnited States Patent [151 Simmons [54] DEVICE FOR A PROJECTILE [7 5] Inventor:

skoga, Sweden {73] Assignee: Aktiebolaget Bofors, Bofors, Sweden [22] Filed: Dec. 16, 1970 [21] Appl. No.: 98,540

[30] Foreign Application Priority Data Bjorn Herman Olof Simmons, Karl- [451 Apr. 3, 1973 FOREIGN PATENTS OR APPLICATIONS 432,297 9/1967 Switzerland ..102/37.6

Primary Examiner-Verlin R. Pendegrass Attorney-Plane, Baxley & Spiecens [57] ABSTRACT A flare releasing missile has a casing including the propellant charge and a hollow projectile fitted to the casing and housing a flare and a parachute therefor. The projectile including its bottom plate is lengthwise split and the projectile parts thus formed are held together by a cap fitted upon the bottom of the projectile until the same is fired. Upon firing of the projectile the cap is forced off thereby freeing the projectile parts and thus the flare with its parachute. The projectile parts are thrown out of the trajectory of the flare by the centrifugal force acting upon the parts due to the spin imparted to the projectile by the rifling in the gun barrel.

4 Claims, 3 Drawing Figures PATENTEUAPRB' 1m 3.724.380

INVENTOR. BJdR/V HERMAN OLOF SIMMONS M.MWS A 1 large calibers, forms a massive, heavy unit.

DEVICE FOR A PROJECTILE The present invention relates to a device for a projectile that can be actuated by a charge in a barrel. The projectile has a case enclosing a space in which the charge is arranged so that when theprojectile is fired a gas pressure is developed which acts upon the projec tile via a bottom plate which is arranged at one end of the case. Further, thebottom plate is arranged so that it can be separated from the case when, for instance, a flare placed in said space and carried by a parachute is expelled from the vehicle part.

As an example of a projectile of said kind can be mentioned a projectile for a pyrotechnical flare, which flare is thus placed in the space in the projectile from which it is released at a predetermined time after the projectile has been fired, after which, ignited and depending from the parachute, it falls down towards the ground.

As mentioned above, the propelling unit develops the gas pressure that achieves the propelling force for the projectile, and the outside of the bottom plate on the projectile constitutes a substantial part of the surface upon which the gas pressure acts which, however, as a rule also comprises parts of the outside of the case at one end of the case. From this it will be obvious that the bottom plate, at least in the case of projectiles of For projectiles of the kind belonging to this category, the massive, heavy bottom plate has involved serious drawbacks, owing to the fact that when the flare depending from the parachute has been expelled from the space in the projectile, the bottom plate has remained in the trajectory of the flare and has followed the flare, so that when its parachute has opened and braked the flare, the bottom plate has hit the parachute, causing damage to this.

In order to eliminate this problem, it has been proposed to give the bottom plate an eccentric shape, and the bottom plate, as a consequence of the angular rotation the projectile has obtained around its axis of symmetry has been given a trajectory that deviates from that of the flare. However, it has been found that it has not been possible to give the bottom plate sufficient eccentricity, as an eccentricity of the size required would jeopardize the functioning of the projectile itself. Insufficient eccentricity has involved that the deviation of the trajectory of the bottom plate in relation to the trajectory of the flare has not been sufficiently large, and the risk that the bottom plate would hit the parachute has still been present.

The present invention relates to a device that solves the above-mentioned problem entirely, without any form of eccentricity of parts of the projectile being necessary, which thus involves that the original high degree of functioning of the projectile itself is retained. The characterizing feature of a device according to the invention is that the bottom plate is composed of a predetermined number of parts, the section surfaces of which extend between the outside and inside of the plate, and further that the bottom plate on its outside is provided with a cap that keeps the parts together and extends at least over the section or sections, and ,which also prevents gas from penetrating into the space and which can also be separated when the flare is expelled from the space.

An embodiment which has the significative characteristics of the invention will be described in more detail in the following, with reference to the attached drawings, in which FIG. 1 shows a side view of a complete round consisting of a projectile and a charge;

, FIG. 2 shows a side view and partly in cross-section oneend of a bottom plate arranged on case of the projectile;

, FIG. 3 shows, in perspective, a detailed view of the bottom plate.

In FIG. 1, 1 shows a charge assembled with a projectile 2, which has a case 3. The charge is arranged so that, when the projectile is fired, it will develop a gas pressure that acts upon the projectile through an actuation surface which consists partly of the outside 4 of the case at one end of the case, and partly of the bottom plate 5.

In FIG. 2, 6 indicates a space contained in the case 3. The bottom plate 5 is composed of two identical, sector-formed parts, one of which is shown in FIG. 2. The section surface of the sector-formed parts extends between the outside 5a of the plate and its inside 5b through an axis of symmetry 7 given to the projectile, and the parts moreover, with their semi-arced outer sections, also cover the major portion of the end surface of the case 3 as well as the end surface of a sup porting ring 8 comprised in the projectile, which has a surface 8a which coacts with the inside surface 30 of the case. On its outside 5a, the bottom plate is covered by a cap 9, which is made in such a way that it keeps the two parts of the bottom plate together from the time when the projectile has been fired from the barrel until its flare is to be expelled from the projectile, and also prevents the gases that are developed when the projectile is fired from entering into the space 6 via the section surfaces of the parts. The cap is fastened in the case 3 and can be separated from said case when the flare is expelled from the projectile.

In principle, the bottom plate composed of the two sector-formed parts substantially has the form of a hemispere, which at the section surfaces gives a pressure stress equal to the pressure stress in the other parts of the bottom plate that have not been cut. Furthermore, for practicalreasons, the assembled bottom plate shown in the example of the embodiment has an outer form resembling that of a truncated cone, which has its wide part facing the end surface of the case. The reference designation 10 shows a member that coa'cts with the rifling in the barrel in order to obtain the rotation of the projectile around its axis of symmetry.

FIG. 3 shows the two sector-formed parts of the bottom plate 5, and with a cut 11 between the sectors. From FIGS. 1-3 it will be noted that the embodiment shown of the bottom plate causes the sectors comprised in the bottom plate to be pressed against each other as a consequence of the forces developed by the gas pressure acting upon the actuation surface substantially towards one and the same point 12 in the axis of symmetry 7. From FIG. 3 it will also be noted that the parts in the bottom plate, when the cap is removed in connection with the flare being expelled from the space, will be thrown far out from the trajectory of the charge in different directions, as a consequence of the centrifugal forces arising owing to the rotation of the plate around its axis of symmetry 7. There is no risk whatsoever that any of these parts will follow the flare and hit its parachute. The comparatively light cap will be braked very heavily by the air resistance when the flare is expelled and thus will not involve any risk whatsoever for the parachute.

The device is not limited to the embodiment described above as an example, but can be subject to modifications within the scope of the following claims. Thus, the bottom plate can be composed of parts of a quantity other than two. The quantity should be at least two, and should be limited only by what is feasible in practice. Nor is the invention limited to sector-formed parts of parts of equal size.

I claim:

1. A device including a separable unit and arranged to be fired from a rifled barrel, said device comprising in combination:

a shell casing containing an ignitable gas generating charge and a projectile fitted into an open end of the shell casing to impart a longitudinal and rotary acceleration to the projectile by the gas pressure generated by ignition of the charge in the shell casing, said projectile being hollow and open at its end facing the shell casing for accommodating in the projectile a unit arranged to be expelled from the projectile through the open end thereof a predetermined period of time after firing of the projectile, and'a bottom member abutting against the projectile at the open end thereof to close said end until said unit is expelled from the projectile, said bottom member comprising at least two complementary equally sized sectors abutting in a plane in registry with the axis of symmetry of the projectile, said sectors having sides inwardly slanted from the open projectile end toward the outer ends of the sectors and a cap covering the outwardly facing surfaces of said sectors and overlying said open projectile end for locking the sectors together and detachably securing the same to the projectile.

2. The device according to claim 1 wherein said sectors have a frusto-conical peripheral outline in a plane parallel to and in registry with the axis of symmetry of the projectile.

3. The device according to claim 1 wherein said sectors define, in conjunction, a frusto-conical configuration, the wide end of said configuration abutting against the rim at the open end of the projectile, the abutting surfaces of the sectors coinciding with the axis-of symmetry of the projectile.

4. The device according to claim 1 wherein said sectors have, in conjunction, a substantially hemispherical configuration, the flat sides of the sectors facing the open end of the projectile and the plane dividing the sectors coinciding with the axis of symmetry of the projectile. 

1. A device including a separable unit and arranged to be fired from a rifled barrel, said device comprising in combination: a shell casing containing an ignitable gas generating charge and a projectile fitted into an open end of the shell casing to impart a longitudinal and rotary acceleration to the projectile by the gas pressure generated by ignition of the charge in the shell casing, said projectile being hollow and open at its end facing the shell casing for accommodating in the projectile a unit arranged to be expelled from the projectile through the open end thereof a predetermined period of time after firing of the projectile, and a bottom member abutting against the projectile at the open end thereof to close said end until said unit is expelled from the projectile, said bottom member comprising at least two complementary equally sized sectors abutting in a plane in registry with the axis of symmetry of the projectile, said sectors having sides inwardly slanted from the open projectile end toward the outer ends of the sectors and a cap covering the outwardly facing surfaces of said sectors and overlying said open projectile end for locking the sectors together and detachably securing the same to the projectile.
 2. The device according to claim 1 wherein said sectors have a frusto-conical peripheral outline in a plane parallel to and in registry with the axis of symmetry of the projectile.
 3. The device according to claim 1 wherein said sectors define, in conjunction, a frusto-conical configuration, the wide end of said configuration abutting against the rim at the open end of the projectile, the abutting surfaces of the sectors coinciding with the axis of symmetry of the projectile.
 4. The device according to claim 1 wherein said sectors have, in conjunction, a substantially hemispherical configuration, the flat sides of the sectors facing the open end of the projectile and the plane dividing the sectors coinciding with the axis of symmetry of the projectile. 